For the plant phases, try to avoid using Polar Vortex or Thunderblight. Your stronger attacks like Shadow Flare (which can crit one shot) or Fireball will often do only 1 damage to the big plants, because Thunderblight and Polar Vortex hit multiple times in 1 second, and the other side would have to hit the same plant during those split second periods for your main attacks to not do 1 damage.
For the plant phases, try to avoid using Polar Vortex or Thunderblight.
Your stronger attacks like Shadow Flare (which can crit one shot) or Fireball will often do only 1 damage to the big plants, because Thunderblight and Polar Vortex hit multiple times in 1 second, and the other side would have to hit the same plant during those split second periods for your main attacks to not do 1 damage.